JPH0144131B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention includes a heating means mainly used in compression molding or transfer molding used for molding thermosetting resins, or injection molding of thermoplastic resins molded at particularly high temperatures. This invention relates to a mold for resin molding.

Compression molding equipment, which mainly molds thermosetting resins, weighs the material into the cavity of a heated mold and molds it by applying heat and pressure. Molding material is put into a pot, heated here to plasticize the material, and then pressure is applied to the material, which is then transferred into the cavity of a mold and molded.

Furthermore, in injection molding apparatuses that mold thermosetting resins, and especially in injection molding of thermoplastic resins that are molded at high temperatures, a heater is provided in the mold to heat the mold.

In either case, conventional equipment heats the mold, but in the case of small molds, a heating plate with heating wires is attached to the mold mounting surface and heating is performed by heat conduction. In the case of large molds, the mold was heated by either installing a cartridge heater in the mold or by circulating hot oil within the mold. With such a configuration, it is difficult to equalize the temperature of each part of the mold.
Further, there was a problem in that the temperature of each part of the mold could not be controlled accurately and immediately in response to commands.

The present invention has been made based on the above-mentioned viewpoints, and its purpose is to reduce the manufacturing cost of molds, to easily and accurately control the temperature of molds, The object of the present invention is to provide a mold for resin molding that can reduce pores, distortion, etc. of a product.

Therefore, the above purpose is to provide a through hole in the center of the fixed platen side template fixed to the fixed platen side mounting plate and the movable platen side template attached to the receiving plate, and to Inside the hole is a generally disc-shaped lower cavity block that has an induction heating coil inside and forms one end surface of the resin molded product, and an induction heating coil on the outer peripheral surface that forms the outer peripheral surface of the resin molded product. This is achieved by a resin molding mold that is made up of an upper cavity block that has an internal induction heating coil and a core that forms the other end surface and inner surface of the resin molded product, each of which is replaceably attached. .

Hereinafter, the details of the present invention will be explained based on the drawings. The drawings are explanatory diagrams showing a closed state of a compression molding mold, which is an embodiment of the resin molding mold according to the present invention.

In the figure, 1 is the fixed plate side mounting plate, 2 is the fixed plate side template, 3 is the core, 3a is the coolant flow path, 4 is the movable plate side template, 5 is the upper cavity block, and 6 is the lower cavity. Block, 7, 7 is guide pin, 8, 8
is a guide pin bush, 9 is a receiving plate, 10, 10 is a spacer block, 11 is an ejector pin, 1
2 is a return pin, 13 and 14 are ejector plates, 15 is a movable side mounting plate, and 16, 16 are induction heating coils.

The fixed plate side mounting plate 1 is attached to a mold mounting fixed plate of a compression molding machine (not shown) via a bolster.

The fixed platen side template 2 is fixed to the fixed platen side mounting plate 1, and the movable platen side receiving plate 4 is fixed to the receiving plate 9, and the fixed platen side template 2 and the movable platen side template 4 A through hole is provided in the center of each.

Each of the through-holes has an induction heating coil 16, 16 inside, and a substantially disc-shaped lower cavity block 6 forming one end surface of the resin molded product.
and has induction heating coils 16, 16 on the outer peripheral surface,
An upper cavity block 5 forming the outer peripheral surface of the resin molded product and a core 3 having induction heating coils 16, 16 inside and forming the other end surface and inner surface of the resin molded product are each attached replaceably. It is being

Thus, a cavity is formed between the core 3 and the upper cavity block 5 and lower cavity block 6, and this cavity is formed in accordance with the external shape of the desired product.

As mentioned above, the induction heating coils 16, 16 are arranged approximately evenly on the outer periphery of the upper cavity block 5, inside the lower cavity block 6, and inside the core 3, and are connected to a power source (not shown). An alternating current is supplied by the device and the upper cavity block 5, lower cavity block 6 and core 3 are each inductively heated.

Generally, a coil called an inductor is wound around a cylindrical conductor, or the magnetic flux generated by the inductor is placed so that it crosses and penetrates the surface of the conductor.
When an alternating current is passed through this inductor, eddy currents are generated in the conductor due to electromagnetic induction, and the conductor generates heat due to the eddy current loss generated at this time.

In this case, since the alternating current has a skin effect, the eddy current concentrates on the surface of the conductor and decreases exponentially toward the center.

The depth of this eddy current is determined by the frequency of the alternating current supplied to the inductor, so by appropriately setting this frequency, the depth of penetration can be freely changed.

The receiving plate 9 is supported by spacer blocks 10, 10, and supports the movable mold plate 4.

The ejector pin 11 is attached with its lower end sandwiched between the ejector plates 13 and 14, and when the ejector plates 13 and 14 move upward, the ejector pin 11 interlocks with the ejector plates 13 and 14 to eject the molded product. .

The return pin 12 passes through the receiving plate 9 and the movable mold plate 4 and reaches the mold separation surface of the fixed mold plate 2, and when the lower mold is pushed up, it comes into contact with the fixed mold plate 2. Push down the ejector plates 13 and 14 to the predetermined position.

The movable side mounting plate 15 is attached to a mold mounting movable platen of a compression molding machine (not shown) via a bolster.

Therefore, at the beginning of each process, the mold mounting movable plate of the compression molding machine (not shown) is lowered, and the movable mold plate 4 and the fixed mold plate 2 are opposed to each other with an appropriate interval between them. are doing.

In this state, alternating current is supplied to the induction heating coils 16, 16 from a power supply device (not shown), and the upper cavity block 5, lower cavity block 6, and core 3 generate heat by induction heating.

The heat generated by this induction heating has 2 to 3 times better power efficiency than heating using electric heating wires, etc., and is also inexpensive and durable. The upper cavity block 5, the lower cavity block 6, and the core 3 themselves are directly heated, and each induction heating coil 16, 16 is divided into a plurality of parts. Since the upper cavity block 5, the lower cavity block 6, and the core 3 each have a plurality of them arranged so as to be partially evenly distributed, it is possible to heat the parts and the whole as desired. This allows accurate temperature control.

In addition, as the induction heating coils 16, 16,
An inductor having a coil wound around an iron core may also be used.

Next, a certain amount of molding material is weighed and put into the heated upper cavity block 5 and lower cavity block 6 of the mold, and a compression molding machine (not shown) is used.
The mold mounting movable platen rises, the movable mold plate 4 is pushed up, and the molding material plasticized by heat and pressure is formed between the core 3, upper cavity block 5, and lower cavity block 6. and formed into the desired shape.

Furthermore, the upper cavity block 5, lower cavity block 6, and core 3 are further heated by induction heating to harden the molding material in the cavity.

After the molding material has sufficiently hardened, the power supply to the induction heating coils 16, 16 is stopped, and a cooling liquid is supplied from a cooling liquid supply device (not shown) to the cooling liquid flow path 3a and is circulated to cool the core 3. do.

After this, the mold mounting movable plate of the compression molding machine (not shown) is lowered, the movable mold plate 4 is lowered and the mold is opened, and the ejector plates 13 and 14 are pushed up and the ejector pin 11 is moved. Push out the product,
The product is removed.

Since the present invention is constructed as described above, the present invention heats the mold uniformly and controls the temperature accurately and in response to commands, thereby eliminating pores and distortions in the product. can be reduced.

It should be noted that the present invention is not limited to the embodiments described above. That is, for example, although a compression molding mold is shown in this example, it goes without saying that it can also be implemented as a transfer molding mold or an injection molding mold. It is intended to encompass all modifications and embodiments that would readily occur to those skilled in the art.

[Brief explanation of drawings]

The drawing is an explanatory view showing one embodiment of a resin molding die according to the present invention. 1...Fixed side mounting plate, 2...Fixed side template plate, 3...
... Core, 4 ... Movable side template, 5 ... Upper cavity block, 6 ... Lower cavity block,
7, 7...Guide pin, 9...Socket plate, 10,10
... Spacer block, 11 ... Ejector pin, 12 ... Return pin, 13, 14 ... Ejector plate, 15 ... Movable side mounting plate, 1
6,16...Induction heating coil.

Claims (1)

[Claims] 1 A through hole is provided in the center of the fixed platen side template 2 fixed to the fixed platen side mounting plate 1 and the movable platen side template 4 attached to the receiving plate 9, and a through hole is provided in each of the through holes. A substantially disc-shaped lower cavity block 6 has an induction heating coil 16 inside and forms one end surface of the resin molded product, and has an induction heating coil 16 on the outer peripheral surface and forms the outer peripheral surface of the resin molded product. A mold for resin molding, in which an upper cavity block 5 and a core 3 having an induction heating coil 16 inside and forming the other end surface and inner surface of the resin molded product are respectively replaceably attached.